Let's Shed Some Light on Photons!

How many photons does a certain green light bulb emit in one hour?

The green light bulb emits at a single wavelength of 550 nm, consumes 55 W of electrical power and is 75% efficient in converting electrical energy into light.

The Lightbulb's Photon Emission Explained

The number of photons emitted by the bulb in one hour can be calculated based on the information provided. Let's break it down step by step:

First, we need to determine the power output of the bulb that is converted into light energy. Since the bulb is 75% efficient, we multiply the power consumption by the efficiency to get the useful power output: 55 W * 0.75 = 41.25 W.

Next, we need to calculate the energy of a single photon using the equation E=hc/λ, where h is Planck’s constant (6.626 x 10^-34 m^2kg/s), c is the speed of light (3 x 10^8 m/s), and λ is the wavelength in meters. The given wavelength is 550 nm, which is 550 x 10^-9 m when converted.

By substituting the values into the equation, we find that the energy of one photon is approximately 3.61 x 10^-19 Joules.

Finally, the number of photons emitted per second can be calculated by dividing the total energy emitted per second by the energy of one photon. Multiplying this result by the number of seconds in one hour (3600) gives us the total number of photons emitted by the bulb in one hour.